This invention relates to certain improvements in a clutch and brake mechanism particularly adapted for but not limited to smaller horsepower application.
The applicant is a joint inventor on an application filed Feb. 2, 1976, Ser. No. 654,214 for a clutch and brake mechanism. That earlier application relates to and describes a low torque clutch. At least in the case of lawn mowers, the low torque clutch has not proven to advantage. In heavy grass, a low torque clutch can be subjected to considerable slippage between drive and driven members, giving rise to the generation of considerable heat, and even possible fire hazzard when operating in dry grass. Further, the heat will serve to anneal the clutch springs and result in an even lower clutch capacity. Shorter clutch life is also to be expected.
Thus, for lawn mowers and other applications, a high torque, or at least a higher torque clutch is preferred to minimize clutch slippage and consequent heat build-up in the clutch mechanism. With a higher torque capability, the engine will be lugged down and killed if it is overloaded and yet is protected when an obstruction is encountered. It is generally an object of this invention to provide a clutch and brake mechanism of higher torque capability.
For good clutch and brake operation, it is important that the clutch and brake surfaces remain clean and dry. Clippings, sawdust, dirt, oil and other foreign matter are deleterious to proper clutch and brake engagement. It is also an object of this invention to substantially preclude the entry of foreign matter into the clutch-brake housing and thus possibly interfere with the clutch and braking operations.
The invention contemplates the use of a brake band for declutching and stopping rotation of the driven member without interrupting the rotation of the drive member. Further aspects of the invention relate to the mounting of the brake band, utilization of the brake band to aid in keeping the braking surface clean, and provision for the cut-off of the power source in the event the brake band should fail.